Evaluation of the Leaf of a Range of Tree Legumes as a Source of Nitrogen for Crop Growth

Abstract

SUMMARYThe leaf mulch of the tree legumes Acacia cunninghamii, A. fimbriata, Calliandra calothyrsus, Gliricidia sepium, Leucaena leucocephala and Sesbania sesban was evaluated as a source of nitrogen for maize growth in glasshouse pot experiments. The mulch of Sesbania sesban resulted in the largest yields of maize stover but yields were less than those that resulted from application of equivalent rates of fertilizer nitrogen. The mulches of Gliricidia and Leucaena also produced a yield response in maize but those of Calliandra and the two Acacia species were ineffective as sources of nitrogen in the short term. Sesbania mulch at the equivalent of 5 t dry matter ha-1 produced a maize yield similar to that obtained with 75 kg N ha-1. The poor response to Calliandra and Acacia mulch may be associated with the high polyphenol and/or lignin content of the leaf of these species.